Diaphragm cartridge and pump having a diaphragm cartridge

ABSTRACT

A diaphragm pump includes a diaphragm cartridge assembly. The diaphragm cartridge is a self-contained unit having a diaphragm defining a pumped fluid side and a hydraulic fluid side and a seat receiving the hydraulic fluid side of the diaphragm and having a center opening. A biasing rod mounts to the diaphragm on the hydraulic fluid side and extending through the opening of the seat. A valve guide at an extended end of the biasing rod and a valve spool slidably mounts on the valve guide. A biasing element engages the seat and the valve guide. The pump may also include valve cartridges including a combined inlet check valve and discharge check valve.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to a diaphragm pump and in particular to a hydraulically driven diaphragm pump with a removable self-contained diaphragm cartridge.

2. Description of the Prior Art

Diaphragm pumps are hydraulically driven pumps in which the pump fluid is displaced by a diaphragm that is deflected by hydraulic fluid pressure. Such pumps provide good value and efficiency while being reliable. Such diaphragm pumps utilize a valve system that controls the volume of oil on the hydraulic side of the diaphragm. Such systems are shown for example in U.S. Pat. No. 7,425,120 to Hembree and assigned to Wanner Engineering, Inc. The valve system of the diaphragm pump is configured with the center of the diaphragm attached to a rod, generally referred to as a bias rod that actuates a valve spool and also provides attachment for a spring that applies a biasing force to the diaphragm.

Although such pump systems provide good performance and reliability, further improvements are possible. Diaphragm pumps need to be serviced periodically and in pumps with such valve systems, the diaphragm must be detached from the rod to gain access to the valve components and other pump components. The spring of such a valve system must be supported or attached to a non-moving surface behind the diaphragm and requires further disassembly and assembly to remove the diaphragm. Therefore, if the diaphragm must be replaced, it also requires removal of the rod attachment. In such a pump, the diaphragm must be pulled forward to detach the diaphragm from the bias rod in order to gain access to the rod. Moreover, if the spool valve and bias rod assembly are removed, the plate behind the diaphragm must also be removed. Other known designs require a fastener that passes through the diaphragm but which still requires access to the rod behind the diaphragm so that it can be held while the fastener is unscrewed. All of these configurations require removal and disassembly of multiple components for servicing and may raise difficulties in accessing and/or gripping the components to remove them. The assembly and disassembly of the components is compounded by having a tensioned spring that must be attached and detached and may be propelled from the assembly or could propel other components from the pump or diaphragm, thereby raising the possibility that parts may be lost.

Therefore, it can be seen that a new and improved diaphragm pump with a diaphragm cartridge is needed that allows a simpler system for removing the diaphragm and valve without detaching the diaphragm from the rod. Moreover, such a diaphragm pump and valve system should avoid having to disassemble the pump further than removal of the fluid head to gain access to the diaphragm. The present invention addresses these as well as other problems associated with diaphragm pumps and valve systems.

SUMMARY OF THE INVENTION

The present invention is directed to a diaphragm pump having a self-contained removable diaphragm cartridge. The diaphragm cartridge may be removed as an assembly and serviced or simply replaced with another diaphragm cartridge. Removal of the diaphragm cartridge does not require removal of other elements and also does not require special tools for manipulating the diaphragm. The diaphragm cartridge includes a diaphragm connected to a bias rod, which is connected to a valve guide. A valve spool slides within a decreased thickness section of the valve guide and moves between shoulders at opposite ends of the narrowed section. The valve spool moves to open or close an overfill valve and an underfill valve. Under normal operating conditions, the valve spool covers both the overfill valve and the underfill valve.

The diaphragm and bias rod are held against the diaphragm seat by a spring. The diaphragm cartridge is properly oriented by an alignment pin to ensure that a passage at the top of the diaphragm aligns with an air bleed line. The diaphragm deflects in a reciprocating motion between a forward position at top dead center and a retracted position to provide a fluid pumping action. The diaphragm cartridge is positioned between a hydraulic plate and a leak detection plate in one embodiment with the leak detection plate clamped between a manifold and a hydraulic plate.

The diaphragm cartridge includes the self contained assembly with the diaphragm, bias rod, valve guide, valve spool, diaphragm seat and springs. Therefore, the entire cartridge may be removed without any disassembly of the various elements of the cartridge. Moreover, the diaphragm cartridge avoids use of a spring attachment or separate valve that requires connection to a hydraulic plate. The diaphragm seat may be easily accessed and engaged so that the cartridge does not require access behind the diaphragm and special tools as is typically required with prior art designs. A further advantages is that the hydraulic plate may be left in place and therefore oil may be left in the crankcase when changing or servicing diaphragms.

According to a further aspect of the invention, check valve cartridges may also be employed in conjunction with a diaphragm cartridge. Multiple check valve cartridges may be used in a single pump with each diaphragm having an associated check valve cartridge. Each check valve cartridge is configured as a combination inlet check valve and discharge check valve. As with the diaphragm cartridge, the check valve cartridge is a completely self-contained assembly and configured and accessed so that no additional elements need to be removed in order to service and access the inlet check valve and/or the discharge check valve.

The present invention provides a system that is more reliable, easier and much simpler for access and maintenance, especially when performing maintenance in the field that is not possible with prior art diaphragm pumps that require disassembly of the multiple various elements by using a system configured with cartridges.

These features of novelty and various other advantages that characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings that form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, wherein like reference letters and numerals indicate corresponding structure throughout the several views:

FIG. 1 is a perspective view of a diaphragm pump according to the principles of the present invention;

FIG. 2 is a side sectional view of the diaphragm pump shown in FIG. 1 with the diaphragm at a first position;

FIG. 3 is a side sectional view of the diaphragm pump shown in FIG. 1 with the diaphragm at a second position;

FIG. 4 is a side elevational view of a diaphragm cartridge with the diaphragm at the position shown in FIG. 2;

FIG. 5 is a side elevational view of a diaphragm cartridge with the diaphragm at the position shown in FIG. 3;

FIG. 6 is a side sectional view of a diaphragm cartridge with the diaphragm at the position shown in FIG. 2;

FIG. 7 is a side sectional view of a diaphragm cartridge with the diaphragm at the position shown in FIG. 3;

FIG. 8 is a perspective view of the diaphragm cartridge shown in FIG. 2;

FIG. 9 is an exploded perspective view of the diaphragm cartridge shown in FIG. 2;

FIG. 10 is a side sectional view of a portion of a second embodiment of a diaphragm pump according to the principles of the present invention;

FIG. 11 is a sectional view of the manifold for the pump shown in FIG. 1;

FIG. 12 is a perspective view of a check valve cartridge for the pump shown in FIG. 1;

FIG. 13 is a first side elevational view of the check valve cartridge shown in FIG. 12;

FIG. 14 is a second side elevational view of the check valve shown in FIG. 12;

FIG. 15 is a sectional view of the check valve cartridge taken along line 15-15 of FIG. 13 and with the check valves in a first position;

FIG. 16 is a sectional view of the check valve cartridge taken along line 15-15 of FIG. 13, but with the check valves in a second position; and

FIG. 17 is an exploded perspective view of the check valve cartridge shown in FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings and in particular to FIG. 1, there is shown a fluid pump such as a hydraulically driven diaphragm pump, generally designated (20). The diaphragm pump is driven by connection to a rotating crankshaft (36) mounted in a crankcase (22). A manifold (26) includes an inlet passage (146) and an outlet passage (148) that houses one or more check valves. The housing may include multiple diaphragms and associated components connected to the crankshaft (36).

Referring now to FIGS. 2 and 3, the pump (20) includes a self-contained diaphragm cartridge generally designated (50) including a diaphragm (52). The diaphragm (52) is driven by hydraulic fluid that is contained in a hydraulic chamber (30) in a reservoir (28) and a plunger chamber (32) and pumping chamber (34). The hydraulic fluid has access to the diaphragm cartridge (50) through the hydraulic chamber (30). The hydraulic fluid is forced against the diaphragm to deflect the hydraulic side of the diaphragm (52) and impart a pumping action. The piston housing (24) defines the reservoir (28), a transfer hydraulic chamber (30) and a plunger chamber (32). The pumping chamber (34) includes an overfill valve (72) and an underfill valve (74). The crankshaft (36) includes a connecting rod (38) attached to a slider (40) in the crankcase (22). The slider (40) is connected to a piston-type plunger (42) that reciprocates and drives the hydraulic fluid from the hydraulic chamber (30) to engage the diaphragm (52). A passage (66) provides fluid communication between the plunger (42) and the diaphragm (52). Moreover, a spool bore (76) provides further fluid communication to the diaphragm (52). It can be appreciated that in some embodiments, the crankshaft (36) may attach to multiple different diaphragms within the same pump and include offset portions along the shaft so that individual diaphragms are synchronized to pump at different stages of the pumping stroke. Passage through the manifold (26) is suctioned in and discharged through the hydraulic chamber (30) by the diaphragm (52). The diaphragm (52) is typically relatively large in diameter and configured to deflect a relatively small amount. The short stroke of the diaphragm (52) is driven by the larger stroke of the plunger (42). The longer stroke of the plunger (42) allows the plunger (42) to use a smaller diameter and impart smaller loads on the crankshaft (36) and crankcase (22) of the pump (20) and therefore imparts less stress.

The manifold (26) houses inlet and discharge check valves. In one embodiment, the pump (20) includes a combined inlet valve and discharge check valve assemblies, which as explained hereinafter, may be configured as a check valve cartridge (100) including an inlet check valve (102) and a discharge check valve (104) for each of the diaphragms (52). The check valves and provide for suction and discharge of the pump fluid into the inlet passage (146) and out through the outlet passage (148).

Referring now to FIGS. 4-8, the diaphragm cartridge (50) is a self contained assembly that is easily removable as a unit for service and repair. The diaphragm cartridge (50) includes the diaphragm (52) that is connected to a bias rod (54). The bias rod (54) attaches to a valve guide (56) with an attachment screw (58). The valve guide (56) has a section with a decreased diameter and a valve spool (60) slides within the space having a decreased diameter created by the valve guide (56). The valve spool (60) moves between the shoulders formed on opposite ends of the decreased diameter section of the valve guide (56). As shown in FIGS. 2 and 3, the valve spool (60) is movable to cover up openings to the overfill valve (72) and the underfill valve (74). Under normal operating conditions, the valve spool (60) covers the openings to both the overfill valve (72) and the underfill valve (74). The valve spool (60) is movable from the normal position to a second position in which the valve spool (60) covers the opening to the overfill valve (72), but uncovers the opening to the underfill valve (74) to provide fluid flow between the reservoir (28) and the hydraulic chamber (30). The valve spool (60) is also movable to a third position in which the spool (60) covers the opening to the underfill valve (74) but exposes the opening to the overfill valve (72) to provide fluid communication to the plunger chamber (32). The valve spool (60), the underfill valve (74) and the overfill valve (72) ensure that proper hydraulic fluid levels are maintained.

The diaphragm (52) and bias rod (54) are held against a diaphragm seat (62) by a spring (64). The diaphragm seat (62) defines a center opening for the bias rod (54) and includes a passage (66) located at the top of the diaphragm (52). The passage (66) therefore acts to vent air so that any air trapped at the top of the diaphragm chamber is vented and leaves the system through an air bleed (78) as shown in FIGS. 2 and 3.

In one embodiment, a pin (68) is utilized to properly orient the diaphragm cartridge (50) with the passage (66) located at the top of the diaphragm (52) when the cartridge (50) is inserted in the pump (20). The diaphragm cartridge (50) is shown positioned with the diaphragm (52) at an extended position in FIG. 7. The bias rod (54) moves with the diaphragm (52) and compresses the spring (64). In FIG. 6, the diaphragm (52) is shown moved to the most retracted rearward position with the bias spring (64) pushing the bias rod (54) rearward, or to the right as shown in FIGS. 5-7.

The diaphragm cartridge (50) is clamped between a hydraulic plate (80) and a leak detection plate (82), as shown in FIGS. 2 and 3. The leak detection plate (82) is positioned between the manifold (26) and the hydraulic plate (80). The leak detection plate (82) includes a passage (86) that allows fluid to escape to indicate a leak. Moreover, in a further embodiment shown in FIG. 10, the diaphragm cartridge (50) and pump (20) may be configured without the leak detection system and mounted within a space formed by the manifold (26) and the hydraulic plate (80).

In one embodiment of the present invention, the pump (20) includes one or more check valve cartridges, generally designated (100) mounting in the manifold (26) as shown in FIGS. 10 and 11. As shown most clearly in FIG. 11, multiple check valve cartridges (100) connect along the inlet passage (146) as well as the outlet passage (148). Pumping chamber passages (152) lead from each valve cartridge to an associated pumping chamber (32) for the diaphragm (52) associated with each of the cartridges (100).

Referring now to FIGS. 12-17, the check valve cartridge (100) includes a lower housing (110), a center housing (120) and an upper housing (130). The lower housing (110) connects to the center housing (120) by a removable first pin (118). The first pin (118) is removable when not mounted and held in place once inserted into the manifold (140). Similarly, the center housing (120) attaches to the upper housing (130) by a removable second pin (132). Like the first pin (118), the removable second pin (132) is held in place by the walls of the manifold (140) when the cartridge (100) is inserted. The check valve cartridge (100) is therefore divided into an inlet check valve module and a discharge check valve module. The lower housing (110) includes an inlet passage (112) that connects to the inlet passage (146) of the manifold (26), which forms a header through the manifold (26). The lower housing forms an inlet check valve (102) while the center housing (120) with the upper housing (130) forms a discharge check valve (104). The inlet check valve (102) includes a valve ball (116) that seals to an inlet check valve seat (114) when closed. The inlet check valve (102) includes 0-ring type gaskets or seals (150) including seals engaging the check valve ball (116). Moreover, a cylindrical liner (138) is inserted in each check valve to align the check valve ball (116) as well as holding the gasket (150) in proper position.

Between the valves (102) and (104), the center housing (120) forms a passage (122) connecting to the pumping chamber passage (152) formed in the manifold (26). The center housing (120) forms a seat (128) receiving an 0-ring type gasket (150) and the cylindrical insert (138) holding the gasket in place. The discharge valve ball (126) engages the gasket (150) when the discharge check valve (104) is in the closed position. The pin (132) connects the center housing (120) to the upper housing (130) and acts as a travel limiter for the discharge valve ball (126).

The upper housing (130) includes the hex top (106) or other shape allowing engagement with a conventional wrench, socket or similar tool that allows for applying the tool to turn the cartridge (100). The upper housing (130) also includes a threaded portion (134) mating with complementary threads (142) of the manifold (26) to secure the cartridge (100). Such a configuration provides for easy and simple removal and interchanging of the entire check valve cartridge (100) with conventional tools if maintenance or replacement is required. The upper housing (130) also forms an orifice (136) that aligns with the outlet passage (56) formed in the manifold (26).

The check valve cartridge (100) includes both the inlet check valve (102) and discharge check valve (104) that are automatically actuated by the pumping action of the diaphragm (52). During the suction portion of the diaphragm stroke, the valve ball (116) and the valve ball (126) are positioned as shown in FIG. 15. The suction from the diaphragm (52) pulls the inlet valve ball (116) upward to disengage from the seat (114) and the gasket (150) so that fluid may pass in through the inlet passage (112), through the inlet valve (102) and through the passage (122) connecting to the pumping chamber passage (152) leading to the pumping chamber (34). The travel of the inlet valve ball (116) is limited by the lower pin (118) and allows fluid to pass around the valve ball (116) and through the inlet check valve (102).

During this portion of the pumping stroke of the diaphragm (52), the discharge valve ball (126) remains in engagement with the discharge check valve seat (128) and the gasket (150). This configuration prevents pumped fluid from being drawn back in by the diaphragm (52).

Referring now to FIG. 16, during the discharge portion of the diaphragm stroke, the inlet check valve (102) is closed and the discharge check valve (104) is open. The diaphragm (52) forces fluid through the pumping chamber (34) and passages (152) and (122) to engage the discharge valve ball (126) and lift the valve ball (126) from engagement with the seat (128) and its respective gasket (150). Travel of the discharge valve ball (126) is limited by the pin (132), but allows fluid to flow around the valve ball (126). The pump fluid passes through the transverse orifice (136) aligned with the outlet passage (148) where it is forced from the manifold (26).

During the pumping portion of the stroke of the diaphragm (52), the inlet check valve (102) is closed with the inlet valve ball (116) engaging the inlet valve seat (114) and its respective gasket (150).

It can be seen that the check valve cartridge (100) provides a simple and reliable operation with only the valve balls (116, 126) moving and having geometry that automatically limits the travel of each of the valve balls (116) and (126) in response to pressure changes from the suction or discharge stroke of the pump (20). The entire cartridge (100) can be removed and replaced or removed and serviced or maintained by simply unscrewing the cartridge (100) with a conventional wrench or socket. Moreover, the cartridge (100) is a completely self-contained assembly and configured and accessed so that no additional elements need to be removed in order to service and access the inlet check valve (102) and/or the discharge check valve (104).

In operation, the crankshaft (36) rotates to cause the piston or plunger (42) to reciprocate. Hydraulic oil in the hydraulic chamber (30) is forced against the diaphragm (52) to cause the diaphragm to reciprocate and provide pumping action. The deflection of the diaphragm (52) to extend and then retract suctions and discharges the pumped fluid.

The diaphragm cartridge (50) includes the diaphragm (52), the bias rod (54), the valve guide (56), the valve spool (60), the diaphragm seat (62) and the springs (64) all in a self-contained assembly. Therefore, the entire diaphragm cartridge (50) may be removed as a single unit without being disassembled. There is no spring attachment or separate valve that requires connection to a hydraulic plate (50). Moreover, the cartridge (50) can be removed without requiring access to the area behind the diaphragm or removal of other pump elements. Therefore the hydraulic plate (80) can be left in place and the crankcase (22) can be left full of oil when changing diaphragms or providing other maintenance or service to the diaphragm cartridge assembly (50). Moreover, the check valve cartridge (100) is a completely self-contained assembly and configured and accessed so that no additional elements need to be removed in order to service and access the inlet check valve (102) and/or the discharge check valve (104). This configuration is much simpler and achieves less time consuming maintenance that eliminates the possibility of losing small parts under the biasing force of a spring as may occur when providing service or maintenance of the prior art diaphragm pumps.

It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

What is claimed is:
 1. A diaphragm pump comprising: a diaphragm cartridge assembly; a diaphragm defining a pumped fluid side and a hydraulic fluid side; a seat receiving the hydraulic fluid side of the diaphragm and having a center opening; a biasing rod mounted to the diaphragm on the hydraulic fluid side and extending through the opening of the seat; a valve guide at an extended end of the biasing rod; a valve spool slidably mounted on the valve guide; a biasing element engaging the seat and the valve guide.
 2. A diaphragm pump according to claim 1, further comprising an air bleed line at an upper portion of the seat in fluid communication with the hydraulic fluid side.
 3. A diaphragm pump according to claim 2, further comprising an air bleed device on the diaphragm assembly to facilitate air removal through the air bleed line.
 4. A diaphragm pump according to claim 1, further comprising an alignment element.
 5. A diaphragm pump according to claim 3, further comprising an alignment element on the diaphragm assembly to align the air bleed device with the air bleed line.
 6. A diaphragm pump according to claim 1, wherein the pump comprises a plurality of the diaphragm cartridge assemblies.
 7. A diaphragm pump according to claim 1, wherein the pump comprises a crankshaft driving a plunger impelling hydraulic fluid against the diaphragm.
 8. A diaphragm pump according to claim 1, further comprising a leak detection system.
 9. A diaphragm pump according to claim 1, further comprising a check valve cartridge including an inlet check valve and an outlet check valve.
 10. A diaphragm pump according to claim 10, further comprising a manifold including an inlet and an outlet.
 11. A diaphragm pump according to claim 1, comprising a plurality of diaphragm cartridge assemblies and a manifold including an inlet and an outlet. wherein the manifold includes a of check valve cartridges.
 12. A diaphragm pump according to claim 11, wherein the manifold includes a plurality of check valve cartridges including an inlet check valve and an outlet check valve.
 13. A diaphragm pump according to claim 12, wherein each of the plurality of diaphragm cartridge assemblies is in fluid communication with an associated one of the plurality of check valve cartridges.
 14. A diaphragm pump according to claim 1, wherein the pump comprises a crankshaft driving a plurality of plungers impelling hydraulic fluid against an associated diaphragm of the plurality of diaphragm cartridge assemblies.
 15. A diaphragm cartridge assembly for a diaphragm pump comprising: a diaphragm defining a pumped fluid side and a hydraulic fluid side; a seat receiving the hydraulic fluid side of the diaphragm and a center opening; a biasing rod mounted to the diaphragm on the hydraulic fluid side and extending through the center opening of the seat; a valve guide at an extended end of the biasing rod; a valve spool slidably mounted on the valve guide; a biasing element engaging the seat and the valve guide.
 16. A diaphragm cartridge assembly according to claim 15, wherein the diaphragm cartridge assembly is a self-contained removable cartridge.
 17. A diaphragm cartridge assembly according to claim 15, further comprising an air bleed line at an upper portion of the seat.
 18. A diaphragm cartridge assembly according to claim 15, further comprising an alignment element. 